//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17

// <chrono>
// class year_month_weekday_last;

// constexpr year_month_weekday_last operator+(const year_month_weekday_last& ymwdl, const months& dm) noexcept;
//   Returns: (ymwdl.year() / ymwdl.month() + dm) / ymwdl.weekday_last().
//
// constexpr year_month_weekday_last operator+(const months& dm, const year_month_weekday_last& ymwdl) noexcept;
//   Returns: ymwdl + dm.
//
// constexpr year_month_weekday_last operator+(const year_month_weekday_last& ymwdl, const years& dy) noexcept;
//   Returns: {ymwdl.year()+dy, ymwdl.month(), ymwdl.weekday_last()}.
//
// constexpr year_month_weekday_last operator+(const years& dy, const year_month_weekday_last& ymwdl) noexcept;
//   Returns: ymwdl + dy.

#include <chrono>
#include <type_traits>
#include <cassert>

#include "test_macros.h"

constexpr bool testConstexprYears(std::chrono::year_month_weekday_last ym)
{
    std::chrono::years offset{23};
    if (static_cast<int>((ym         ).year()) !=  1) return false;
    if (static_cast<int>((ym + offset).year()) != 24) return false;
    if (static_cast<int>((offset + ym).year()) != 24) return false;
    return true;
}

constexpr bool testConstexprMonths(std::chrono::year_month_weekday_last ym)
{
    std::chrono::months offset{6};
    if (static_cast<unsigned>((ym         ).month()) !=  1) return false;
    if (static_cast<unsigned>((ym + offset).month()) !=  7) return false;
    if (static_cast<unsigned>((offset + ym).month()) !=  7) return false;
    return true;
}


int main()
{
    using year                    = std::chrono::year;
    using month                   = std::chrono::month;
    using weekday                 = std::chrono::weekday;
    using weekday_last            = std::chrono::weekday_last;
    using year_month_weekday_last = std::chrono::year_month_weekday_last;
    using years                   = std::chrono::years;
    using months                  = std::chrono::months;

    constexpr weekday Tuesday = std::chrono::Tuesday;
    constexpr month January = std::chrono::January;

    {   // year_month_weekday_last + months
    ASSERT_NOEXCEPT(std::declval<year_month_weekday_last>() + std::declval<months>());
    ASSERT_NOEXCEPT(std::declval<months>() + std::declval<year_month_weekday_last>());

    ASSERT_SAME_TYPE(year_month_weekday_last, decltype(std::declval<year_month_weekday_last>() + std::declval<months>()));
    ASSERT_SAME_TYPE(year_month_weekday_last, decltype(std::declval<months>() + std::declval<year_month_weekday_last>()));

    static_assert(testConstexprMonths(year_month_weekday_last{year{1}, January, weekday_last{Tuesday}}), "");

    year_month_weekday_last ym{year{1234}, January, weekday_last{Tuesday}};
    for (int i = 0; i <= 10; ++i)  // TODO test wrap-around
    {
        year_month_weekday_last ym1 = ym + months{i};
        year_month_weekday_last ym2 = months{i} + ym;
        assert(ym1.year()         == year(1234));
        assert(ym2.year()         == year(1234));
        assert(ym1.month()        == month(1 + i));
        assert(ym2.month()        == month(1 + i));
        assert(ym1.weekday()      == Tuesday);
        assert(ym2.weekday()      == Tuesday);
        assert(ym1.weekday_last() == weekday_last{Tuesday});
        assert(ym2.weekday_last() == weekday_last{Tuesday});
        assert(ym1 == ym2);
    }
    }

    {   // year_month_weekday_last + years
    ASSERT_NOEXCEPT(std::declval<year_month_weekday_last>() + std::declval<years>());
    ASSERT_NOEXCEPT(std::declval<years>() + std::declval<year_month_weekday_last>());

    ASSERT_SAME_TYPE(year_month_weekday_last, decltype(std::declval<year_month_weekday_last>() + std::declval<years>()));
    ASSERT_SAME_TYPE(year_month_weekday_last, decltype(std::declval<years>() + std::declval<year_month_weekday_last>()));

    static_assert(testConstexprYears (year_month_weekday_last{year{1}, January, weekday_last{Tuesday}}), "");

    year_month_weekday_last ym{year{1234}, std::chrono::January, weekday_last{Tuesday}};
    for (int i = 0; i <= 10; ++i)
    {
        year_month_weekday_last ym1 = ym + years{i};
        year_month_weekday_last ym2 = years{i} + ym;
        assert(ym1.year()         == year(1234 + i));
        assert(ym2.year()         == year(1234 + i));
        assert(ym1.month()        == January);
        assert(ym2.month()        == January);
        assert(ym1.weekday()      == Tuesday);
        assert(ym2.weekday()      == Tuesday);
        assert(ym1.weekday_last() == weekday_last{Tuesday});
        assert(ym2.weekday_last() == weekday_last{Tuesday});
        assert(ym1 == ym2);
    }
    }

}